Varnish resin and method of making same



Patentedll une 19; H45

2,378,886 VARNISH nnsm AND METHOD OF MAKING SAME Herbert Ewe Los Angeles, assignor to Monsanto Chemical Company, a corporation of Delaware No Drawing. Application March 18, 1943,

Serial No. 479,592

17 Claims.

My invention relates generally to the production of varnish resins and more particularly to an many products of the paint industry.

The synthetic resins commonly used in the manufacture of varnishes may be divided generally into two main classes, to wit: the phenol improved alkyd varnish resin, useful. in a great resins and the alkyd resins. The latter group of resins, while having many advantages over the phenol type resin, has not come into as wide useas might be because they are very slow through drying and are not very water resistant. However, they have other very desirable, properties such as high gloss, excellent durability, eventual toughness of film, and good baking properties.

By the expression alkyd varnish resin? as.

used herein, I mean to include those synthetic resins which are known as modified polyhydric alcohol polybasic acid resins, which are most commonly made by suitably reacting a polyhydric alcohol, such as glycerine, a polybasic acid, such as phthalic anhydride, and a normally liquid unsaturated fatty oil or unsaturated fatty acid with,

or without additional modifying natural or synthetic resins. In the manufacture of such synthetic resins, the'excess phthalic anhydride may be blown out Wi thCOz at the proper point in their reaction. and volatile thinners'are added.

The normally liquid unsaturated oil or unsaturated fatty acid may be oleic acid, linoleic acid,

In general, I accomplish this major object of my invention by incorporating a substantial quantity of naphthalene, in the manufacture of r the resin at, an early stage in the reaction.-

Another object of my invention is to provide a novel method for producing one phase in an alkyd varnish resinreaction mixture within a much shorter time than is usually necessary when employing a high percentage of. drying oil.

In making alkyd varnish resins, the: order in which the various ingredients must be added to the reaction mixture depends largely upon the particular formula being 'used. 'The guiding principle is to condition "the reaction mixture, so that all ingredients will eventually form one phase as the reaction proceeds. An additional requirement is that 'the resin constituents should form one phaseafter the resin has cooled and also after dilution with the various thinners used.

in the art.

The following examples are. illustrative of the very largenumber of possiblealkyd varnish resin formulas {to which my invention may be applied,

linolenic acid or the various normally liquid unsaturated fatty acid mixtures obtained from natur'al products by saponification of the glycerides thereof. Naturally occurring unsaturated/oils may be corn oil, cotton seed oil, soya bean oil. perilla oil or linseed oil. Cotton seed oil and corn oil are generally considered to be non-drying or semi-drying oils, while linseed, perilla and soya bean oil are considered to be drying oils. For

the purpose of the present invention, unsaturated oils or unsaturated oil acids generally may be employed, Excluded fromthe scope of this invention are the saturated oils or oil acids whether such saturated oil is a natural product or is chemically prepared as by hydrogenation or arylation. An example of an unsuitable fatty acid in my composition is stearic acid. This acid tends to precipitate out of the resin upon cooling and forms waxy films of little or no gloss.

The major object of my invention is to provide an alkydvarnish resin and a method of makin herein illustrated.

but it is to be understood of course that these examples are given purely by way of illustration, and that my invention is applicable to theproduction of alkyd varnish resins other than those Case #1 If the formula contains glycerine, phthalicanhydride, and drying oils, semi-drying oils, or nondrying oils, a satisfactory procedure is to cook the glycerine and oils together at a temperature of 450 F. to 540 F., or even as high :as 550 F.

to 560 F. until one phase is reached, then to add the phthalic anhydride and naphthalene, and

of drying oil acids, all

same, which resin will exhibit improved through drying and water resisting properties to a marked degree, and which will also haveallower acid number, increased durability, a .lower cost of manufacture on a non-volatile basis, enhanced gloss, increaseditolerance' for petroleum solvents, better baking properties, and decreased tendency for polymerized particles to persist in the finishe resin sbillfl' cook tocompletion.

Case #2 If the formula. contains glycerine, phthalic an hydride, drying oils, and drying oil acids in relatively small amounts, the glycerine, oils, and acids may be'cooked until one phase results then the phthalic anhydride' and naphthalene may be added, and the reaction carried to completion.

Case #3 If the formula contains glycerine, phthalic anhydride, drying oils, and relatively large amounts the ingredients, including naphthalene, may be cooked together fromthe start. One phase will result and the resin may be satisfactorily completed.

Case #4 If the formula contains glycerine, phthalic anhydride, and drying oil acids, but no drying oils,

all the ingredients, including naphthalene, maybe added at the beginning of the reaction, and:

1 stage of the action or the reaction and between 540 F. and 550 phthalic anhydride naphthalene.

action mixture v temperature, should then be raised to approxiyellow in color and not very viscous.

" 1 metal 0.48% and cobalt metal 0.06%

. one phase will result so that the resin may be completed. i a

If the formula contains rosin, glyc'erine,

phthalic anhydride, and drying oils, a satisfac tory procedure is to cook the rosin, glycerine, and the. oils together until one phase is obtained, then to add the phthalic anhydride and naphthalene, and cook to completion. a

The same general schedule maybe employed when s'emidrying and non-drying oils or oil acids are employed in whole or in part.

It is important to note at this point that simply dissolving naphthalene ina finished alkyd resin does not accomplish the beneficial results obtained when the naphthalene is added at an early nary ingredients, so that it 'aifect's the course becomes part of the final produet, I v 1 To further illustrate particular embodiments of my invention, 1 will give the followingspeciiic examplesof alkyd varnish resins made by me in the practice of my invention.

- d Example #1 In-"a suitable covered container, such as a 1500 '00., beaker, place 23 grams of linseed oil fatty acids, 220 grams raw perilla oil, and 105 grams U. S. P. glycerine; raise to a temperature of 540- F.in approximately 30 minutesand maintain at phase results, which should be in approximately 40 minutes. The mixture should then be allowed to cool'to approximately 500 F., and 190 grams of addedand then 100 grams of will form one clear phase. The

mately 500 F.

540 F. in about 20 minutes, where it should .be

held for approximately 30 minutes more. The

mixture can then be cooled to approximately 400 F: in 15 minutes; and subsequently thinned to 60% resin with xylol or other suitable volatile solvent. Using the above formula, the losses are approximately 17 grams to the point where the and is cooked with the ordi- At approximately 410 F. the renumber is not simply a dilution efiect oi the, naphthalene, since the acid number,'ba'sed on non-volatile minus naphthalene content, is only 25; whereas as mentioned,, it is 36.7 if the naph- F. until, one transparent in 25 minutes, and from 5009 F'. a)

thalene only plays a sol ute role in the reaction.

Example #2 In a suitable c'overed'container, place grains 1 WW rosin, 62 grams tung oil, 112 grams U. S. P. glycerine, 145 grams perilla oil; heat to approximately 540 F. in about 40 minutes, and hold be tween 540 F. and 550 F.until a clear phase results which should be in approximately 5 minutes.- Cool to 500 F.,'add 190 grams phthalic anhydride, and then grams of naphthalene.

Heat to 500 F. in 50, minutes, hold at 500 F. for 30 minutes, cool to 400 F., and thin to 60% nonvolatile content with xylol or other suitable vola- I tile solvent. The totalcook loss is approximately 56 grams, and the acid number is 18.4. Example #3 Ina suitable cove red container, place 60 grams WW rosin, 62 grams tung oil, grams U. S. P;

glycerine, grams perilla oil, heat to 540 F. in-

approximately 25 minutes; hold between 540 F. and 550 F. until one clear phase results (approximately 7 minutes); cool to 500 F. add

grains of phthalic anhydride, 100 grams ofnaphthalene, and 15 grams of the commercial resin Bakelite BR-254 (a dehyde resin).

utes; cool to approximately 400 F. and thin to 60% non-volatile content ,with xylol' or other suitable volatile solvent.

It will be noted that in each .of the last two examples, I add rosin to the glyc'erine "and drying oil before cooking with phthalic anhydride.

' By this procedure, one clear phase results in a veryshort time-5 and 7 minutes; respectively-in Examples 2 and -3 once the mixture has been "heated to'the required temperature. Heretofore,

it has been necessary, when not employing a drying oil acid, to cook the mixture for quite a long period of time (sometimes an hour or more) until one clear phase results. The rosin added atthis ,early stage of the process reacts with the glyceron non-volatile 50 of the thinner a petroleum solvent of higher'aniused. -I havefound that the percentages of rosin ate lead and cobalt driers to the amounts, lead of non-volabinations. v v

I have found that avarnish made according to-the foregoing directions dries dust free in about l0 minutes, a lit extremely hard and tough in 24 hours, and tha varnish will'stand immersion in water for days without whitening. a That the naphthalene course-or the reaction is shown by the tact that the-"acid number based on non-volatile content of definitely controls the after 4 8,hours air drying, the.

the resin, m'adeaccordlng to the foregoing ex-' ample, is 22.2 while the cal *batch containing acid number of an identino naphthalene, is 36.7.

' Calculation shows that the lowering of the acid 60 tile content. or other suitable varnish drier com- 5 inc to form ester gum and performs the additional function of facilitating the at one reaction phase upon the addition of phthalic anhydride. While the addition 'of rosin to the mixtureat thebeginning produces the beneficial effects just noted, this addition also somewhat lowers the durability of the'resulting product, so

that excessive quantities of rosin should not be set forth in Examples 2 and 3 are about the maximum amount permissible for a satisfactory prodnet i 1 Emmple #4 i In a suitable covered container, place 222 grains perilla oil acids, 126 grams U. S.Prglycerine, 190 grams phthalic anhydride, 100 grams, naphthalene.

minutes, will consist of one clear phase. Heat to 500 F. in 25 minutes, and then to 530 F. in 20 minutes. Cool to 400 F. and thin to 60% para-phenyl-phenol-formal- Heat to 500 F. in approximately 40 minutes and hold for an additional 30 min- 'nment' of Heat to340 F. in approximately 25 at which point thereaction mixture non-volatile content with xylol. The acid number 01' this resin based on non-volatile content will be approx-r imately 13.2, with a total cook loss of ,approx-" imately85 grams.

Experiments have shown that a resin made in; accordance with Example #4, except without the.

naphthalene, has acid number of approximately 36, with a cook loss 0143 grams with the same heat treatment. In all of the foregoing examples, the temperatures given are those read when the thermometer is substantially centered in'the receptacle, and extends down through the liquid to contactthe base or the receptacle. However, due to the reaction, thetemperature is practically uniform throughout the reaction mixture. Example #501) same time and temperature as above in (b). A heavy crust of crystals of phthalic anh'ydride formed on the container walls. The acid value of the resin was 21.5. It was thinned to 60% solids content with mineral spirits, and cobalt and lead driers added. "The color of the varnish was dark, and showed a drying time of more than 2 hours. Exposure to cold water for hours caused a bad whitening of the film.

As previously mentioned, I have found that the naphthalene does not act merely as a solute, but definitely controls the resulting resin complex. This hasbeen established by making different batches of synthetic resins according to the same formulas, all factors being the same except that in one batch naphthalene was added as indicated hereinbefore and in the control batch, no naphthalene was added. In each into a solid content of 50%. The color of the resulting varnish was pale.

Example #50:)

A second varnish was made using the same in-' gredients and the same procedure as above, but excluding naphthalene. .A loss of 8.5 grams was observed upon cooking. During cooking a heavy crust of crystals formed on the container walls. Such crystals may result in loss of phthalic anhydride or cause inhomogeneity of theresin.

The resin was cooled after cooking and thinned with mineral spirits to the same body as the varnish produced in (a) The resulting varnish contained only 30% of solids. The color of the varnish was dark.

The effect upon the body (i. e. viscosity) of the resulting varnish by the presence of naphthalene during the cook is illustrated strikingly by the results obtained with varnishes (a) and (b) of Example 5, above. It is there shown that the naphthalene containing resin can be thinned to the, same viscosity and will then contain a higher solids content than the resin made without'naphthalene. Such a naphthalene containing resin can also bethinned to alower viscosity, and still have the same solids content as a resin made'in the absence of naphthalene. It is ap-.

Example #601) A 40 gram sample of the monoglycerides thus produced was then mixed with 22.5 grams of lene, processed to 550 F. for minutes. 'No crystals formedupon the container walls. The

acid value of t e resin was 19.5. It was then thinned to 60% solids with mineral spirits. .Co-

- halt and lead driers were added. The color was pale and the varnish had a drying time of 2 hours to produce a non-tacky film. Exposedto cold water for 20 hours caused only a slight whitening of the film.

Example #m) A second 40 gram sample of the'monoglyceride produced in (c) was mixedwith 22.5 grams or stance, the resulting varnish made from the resin in which the naphthalene was added during an early stage of the cooking showed a much lower acid number than would be explained by the presence of naphthalene as solute only, and was able to'withstand immersion in water for a long time, whereas the control batches made without naphthalene whitened badly upon 24.

found that any naphthalene added in excess of 20% is substantially wasted in that it boils oil and no appreciable increase of beneficial eflect is obtained. The results obtained by me in the practice of my invention to date indicate that the ideal quantities are between approximately 13 aiid 16% naphthalene, although it will be understood, as mentioned, that lesser or greater amounts may be used with correspondingly different degrees of improvement. Percentages of naphthalene are based upon total resin ingredients, 1. e., upon the total weight of polybasic carboxylic acid, polybasic alcohol, oil or oil acid and naphthalene.

The reaction should be carried out at temperaphthalic anhydride and 12.5 grams oi. 'naphtha- I tures above the boiling point of naphthalene which is 218 C. or 4241i F. and preferably at temperatures above 450 F. The temperature may range between 450 F. and 540 F. or even 550 F. toas much as 560 F.

The reaction is moreover carried out inthe absence of hydocarbon solvents such as naphthas of various types, particularly because of the difficulty of completely eliminating such solvents from the resinous bodies.

. In the formation of the above described varnish resins varying amounts of naphthalene remain .in the final product. The naphthalene lost during the resin forming reaction constitutes about onehalf to three-fourths oi the original quantities employed. This may vary somewhat depending upon the reaction conditions. In general the resin finally contains approximately 3 to about 10% by weight of naphthalene. I

While I have given various specific examples of my invention, they are to be understood as,

illustrative only, and I do not mean to in any way 3 phthalic anhydride and then processed at the* ppendedclaims. I

' sequently limit myself thereto, eiicept as required by the "This application is a continuation-in-part of application Serial No. 293.617, filed 1939. a

' WhatIclaim is: a v 1. The method of producingan alkyd resin September 6.

which includesheating together to a temperature of at least 424.4" F. a monoglyceride of a normally liquid unsaturated fatty acid derived by saponiflcation from a naturally occurring glyceride with phthalic anhydride in the presence, of naphthalene.: 1

2. The method of producing an alkyd resin which comprises heating together at a temperature above the boilingpoint of naphthalene a monoglyceri e of a normally liquid unsaturated 7 fatty acid derived-by saponiflcation from a natu- M ally occurring glyceride with phthalic anhydride' in the presence of naphthalene.

3. The procss defined in claim zihwhich the amount of naphthalene employed is-between 10% and by weight of said resin.

said reaction'mlature and thinning the ame with xylol.

11. The method of producing an alkyd resin. which comprises reacting glycerine, linseed oil fatty acids andphthalic anhydride in the pres ence of naphthalene at a temperature M480 F.,- cooling and thinning the resin by the addition of mineral spirits, to a solids content of about 50%, a

l2. Themethod of producing an alkyd resin which comprises reacting glycerine with cotton I seed oil tov form the corresponding monoglycerides; then ,reacting the monoglycerideswith phthalic anhydride in thepresence ofnaphthalene at a temperature above the boiling point of naphthalene and thinning the product of thereaction with '4. .rrhe process defined in claim 2 in which the heatingis continued until one clear phase results. 5. The method of producing an alkyd resin which includes heating together at a temperature between 450 F. and 550 s. a honhauy liquid oil selected from the class consisting of unsaturated fatty acid oils of natural origin and un saturated fatty acids derived bysaponlflcation from a naturallyoccurringglyceride. with glycerine and phthalicanhydride, said reaction being carried out in the presence of naphthalene.

6. The method of producing an alkyd resin I which includes heating together is. normally liquid oil selected from the class consisting '0! unsaturated fatty acid oils of natural origin and unsaturated fatty acids derived by saponiflcation from. a naturally occurring yceride with glyc- .erine and then heating said prbduct'at a temperature: in excess of 424.4 F., in the presence of naphthalene, with phthalic ,anhydride. 7-. The method defined in claim ,6 in which the amountiof naphthalene employed is approximately 13to-16% by weight of said resin.

- 8.; The method of producing an alkyd resin which comprises reacting glycerinelwith linseed oilfatty acids and raw perilla ,oil at a temperature between 450 F. and5501 F. until one transparent phase results, cooling thelnixture, adding phthalic anhydride and naphthalene. progrespoint of naphthalene. v p I .14. A water -resistant alkyd resin formed by heating to a temperature above 424.4 F. in the presence of naphthalene a normally liquid oil mineral s'pirts.

13. The method of producing an alkyd res n' which includes heating glycerine with a normally liquid oil selected from the class consisting of unsaturated fatty acid oils of natural origin and unsaturated fatty acids derived by saponificatlon from a naturally occurring glyceride to form the corresponding-monoglycerides, and then heating the monoglyoerides with phthalic anhydrlde in the presence of naphthalene said heating being carried out at a temperature above the boiling A selected from the class consisting of naturally occurring unsaturated fatty acid oils and unsaturated fatty acids derived by saponiflcationfrom a. naturally occurring glycerid with glycerine 7 phthalic anhydride.

15. A water-resistant alkyd resin of low acid number formed by heating a-normally liquid oil selected from the class consisting of naturally be curring unsaturated fatty acid oils and unsaturated fatty acids derived by saponifleation fromanaturally occurring glyceride with glycerine and g'then heating the product, in the presence of naphthalenefat a temperature above the boiling naturally occurring glycerides with glycerine to sively heating the mixture to effect a reaction,

then again cooling said reaction mixture and subthinning .the same with a volatile solvent. 9. The method of producing an alkyd resin which comprises reacting glycerine withrosin,

tung oil and perilla oil until a clear phase results, cooling the reaction mixture, adding phthalic anhydride and naphthalene and heating the r'nixture at a temperaturefabove the boiling point of,

naphthalene to effect a reaction, then again cooling said reaction "mixture and thinning the product with a volatile solvent. i

10. The method of producing ah} alkyd resinwhich comprises reacting glycerine, phthaliclanhydride and perilla oil acids in the presence of i naphthalene until one .clear phase results, pro- 8res sively heating the mixture to a temperature oi at'least 424.43 P. to effect a reaction,- cooling resin having a low acid-number and unusually between 500? F. and

' thinning sale mixture.

form the corresponding monoglyoerides. and then heating the monoglycerides with phthalic acid in the presence of naphthalene at -a temperature above the boiling point of naphthalene.

17. The method of producing an alkyd varnish good waterresistance, which includes: cooking a mixture of glycerine, and a substance selected from the group consisting of naturally occurring unsaturated fatty acid oils and unsaturated lattyacids derived by saponlfication from a naturally occurringglyceridaat a temperature, of approachmately 540 F. until one clear phase results; cool 'lng said mixture to apprommately 500 F.; add

ving phthalic anhydride and naphthalene to said mixture; completing thecooking or said mixture 540 R; and cooling and rmnemr is. wanna. 

